Shingle tear strength with fiber mixture of different fibers

ABSTRACT

A coated fiber mat of improved tear strength upon dividing pieces of the coated mat and the coating is provided. The coated mat is a cured, non-woven mat including a mixture of fibers having different fiber lengths. The fibers contain a polysiloxane compound and are fixedly distributed in a binder.

RELATED APPLICATIONS

[0001] This application is a continuation-in-part application of U.S.Ser. No. 09/759,043, filed Jan. 12, 2001, which is acontinuation-in-part application of U.S. Ser. No. 09/484,749, filed Jan.18, 2000, the entire contents of each of which are incorporated hereinby reference.

FIELD OF THE INVENTION

[0002] The present invention relates to a cured, siloxane-containingnon-woven fiber mat having fibers of different lengths that can besuitably employed as a roofing or other building composite requiringimproved tear strength.

BACKGROUND OF THE INVENTION

[0003] In the building composite industry, various methods have beendeveloped in an attempt to improve the mat strength and stability ofnon-woven fiberous mats. Many efforts are focused on modifying thebinder systems. The following patents and publications arerepresentative of such endeavors:

[0004] U.S. Pat. No. 4,335,186 discloses a chemically modified asphaltcomposition where the asphalt is reacted with a nitrogen-containingorganic compound which is capable of introducing to the asphaltfunctional groups that can serve as reactive sites to establish a securechemical bond between the asphalt and reinforcing fillers, blended intothe asphalt, such as glass fibers and siliceous aggregates.

[0005] U.S. Pat. No. 4,430,465 relates to an article of manufacturingcomprising mat fibers, such as glass fibers, that are coated with acomposition comprising asphalt, an alkadiene-vinylarene copolymer, apetroleum hydrocarbon resin and a branched organic amine which isemployed as an anti-stripping agent.

[0006] U.S. Pat. No. 5,518,586 provides a method of making a glass fibermat comprising dispersing glass fibers in an aqueous medium containinghydroxyethyl cellulose to form a slurry; passing the slurry through amat forming a screen to form a wet fiber glass mat; applying a bindercomprising a urea-formaldehyde resin, a water-insoluble anionicphosphate ester and a fatty alcohol to the wet glass fiber mat; andcuring the binder.

[0007] U.S. Pat. No. 5,744,229 discloses a glass fiber mat made with apolymer-reacted asphalt binder. The disclosed binder of the glass fibermat includes an aqueous emulsion of a polymer modified asphalt producedby the reaction of asphalt, a surfactant, and a phenol-, resorcinol-,urea- or melamine-formaldehyde resin.

[0008] U.S. Pat. No. 4,500,600 describes glass fibers coated with a sizecomposition comprising γ-aminopropyltriethoxysilane and an alkoxysilane.

[0009] In addition to modifying the binder systems, some efforts havefocused on increasing the mat strength through the use of fibers havingdifferent lengths. For example, U.S. Pat. No. 4,472,243 provides a sheettype felt material and sheet type roofing material such as shingles androlls made therefrom. The felt comprises 10-60 weight % glass fibershaving varying lengths, 15-80 weight % cellulose fiber and 5-25 weight %binder. The binder include acrylamides, starch, urea resins, phenolresins, sodium silicates, epoxy resins, styrene-butadiene rubber,acrylic, neoprene, and acrylonitrile.

[0010] U.S. Pat. No. 5,585,432 discloses reinforced polymer compositeshaving a uniform mixture of reinforcing fibers having a polymordallength distribution and having polymer particles distributed therein.Fillers such as silicon dioxide, calcium carbonate, magnesium oxide,CaSiO₃ and mica may also be present in the polymer composite.

[0011] Although improved mat strength may be accomplished using fibersof different lengths, this improved strength typically does not holdwhen a shingle is formed by coating the mat with asphalt. In view of theabove drawbacks with the prior art, there is still a continued need toprovide a new and improved non-woven mat which has improved tearstrength even after it is coated with asphalt.

SUMMARY OF THE INVENTION

[0012] The present invention provides a cured, non-woven mat that hasimproved tear strength which strength is also transferable to a roofingmaterial, i.e., shingle, sheet or roll, when the inventive mat is coatedwith asphalt. Specifically, the inventive cured, non-woven mat comprisesa mixture of fibers having different fiber lengths, which fibers containa polysiloxane compound, and are fixedly distributed in a binder. Byusing the differing fiber lengths in conjunction with a polysiloxanecompound, lower weight mats can be produced that render similar shingletear properties as a higher weight mat. The extent of this improvementis dependent on the fiber lengths and the amounts of different fibersemployed.

[0013] Another aspect of the present invention relates to an asphaltroofing material which includes the inventive cured, siloxane-containingnon-woven mat which is coated with asphalt.

[0014] Although several methods of making non-woven fiber mats can beemployed to form the inventive cured, siloxane-containing mat, a wetlaid process where the fibers having differing lengths are dispersed inwhite water to form a wet web derived from a slurry or mat is preferred.Optionally a dispersing agent, emulsifier, lubricant, defoamer,surfactant and/or other conventional excipients can be added to thefiber containing slurry of the present invention. In a mat formingmachine such as a paper pulp apparatus, e.g., a Fourdrinier papermachine, excess water is removed from the slurry to form the web. Abinder such as disclosed in U.S. application Ser. No. 09/759,043 is thenapplied to the wet web as a 5 to 40% aqueous solution, dispersion oremulsion by employing the use of a curtain coater or a dip and squeezeor knife edge applicator. Alternatively, the binder can be sprayed ontothe binder web.

[0015] Following binder saturation of the web, excess binder is removedand a web containing a siloxane polymer is then dried and cured at atemperature of between 200° C.-400° C. for a period of time from a fewseconds to about 5 minutes. The siloxane can be introduced after or inadmixture with the binder solution, or, if desired, a portion or all ofthe siloxane can be introduced into the fiber size or slurry beforeaddition of the binder. The siloxane component is employed in the formof a solution, suspension emulsion or dispersion in water or in anorganic solvent such as isopropanol, cyclohexanol or other inert organicsolvent. For the purposes of the present invention, a coating ofpolysiloxane or asphalt can be added as a top coat on the cured mat.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The sole FIGURE in the present invention is a top plan viewillustrating the separation of a composite which comprises a glass fibermat of the present invention having an asphalt coating which penetratesthe mat.

DETAILED DESCRIPTION OF THE INVENTION

[0017] As stated above, the present invention provides a cured,non-woven mat and an asphalt coated roofing material which products bothexhibit improved tear strength. The inventive cured, non-woven matcomprises a mixture of fibers having different fiber lengths, whichfibers contain a polysiloxane compound, and are fixedly distributed in abinder. Specifically, the inventive cured, non-woven mat comprises fromabout 50 to about 95 weight % of said fibers containing from about 0.001to about 20 weight % of polysiloxane and from about 5 to about 50 weight% of said binder. More preferably, the cured, non-woven mat of thepresent invention comprises from about 65 to about 90 weight % of saidfibers containing from about 0.01 to about 10 weight % of polysiloxane,which fibers are fixedly distributed in from about 10 to about 35 weight% of said binder.

[0018] The fibers of the inventive mat include, but are not limited to:fibers of glass, wood or pulp or particles, polyethylene, polypropylene,polyester, Nylon®, Orlon® or mixtures of these fibers depending on theend use of the mat. When the inventive mat is employed as a roofingshingle, acoustical board, built-up roofing (BUR) or other asphalticcomposite, a majority of the fibers present in the mat are glass fiberswhich are preferably unmixed. For facers or underlayment used indifferent articles of building construction, e.g., divider panels, othersynthetic fibers or wood chips fixed in a mat can be utilized.

[0019] As stated above, the mat fibers employed in the present inventionhave different fiber lengths associated therewith. Specifically, theinventive mat comprises a mixture of fibers where from about 0 to about100 weight % of the fibers have an average length of from about 0.5 toabout 60 mm and from about 0 to about 100 weight % of the fibers have anaverage length of from about 10 to about 150 mm. More preferably, theinventive mat comprises from about 20 to about 80 weight % of fibershaving an average length of from about 10 to about 45 mm and from about20 to about 80 weight % of fibers having an average length of from about30 to about 80 mm. The fibers having differing fiber lengths typicallyhave an average diameter of from about 1 to about 100 μm, with anaverage diameter of from about 5 to about 25 μm being more highlypreferred. The fibers can be obtained from commercial sources or made bytechniques well known to those skilled in the art.

[0020] The polysiloxane component of the inventive mat is a polysiloxanecompound having repeating units of —[SiO]—. The siloxane polymer can bemodified with various substituents which include linear, branched oraromatic end-groups that may optionally contain oxygen, sulfur and/ornitrogen. Generally, the polysiloxanes are classified as polyalkyl-,polyaryl, polyalkylaryl- and polyether-siloxanes. The polysiloxanesfound to be highly useful in the present invention are those having aweight average molecular weight (MW) of at least 600. In a highlypreferred embodiment, the polysiloxane is a polydialkylsiloxanecompound, with polydimethylsiloxane being most preferred.

[0021] Illustrative examples of suitable polysiloxanes that can beemployed in the present invention include, but are not limited to:polyalkylene oxide-modified polydimethylsiloxane-dimethylsiloxanecopolymer (MW=13,000); polyalkylene oxide-modifiedpolydimethylsiloxane-dimethylsiloxane copolymer (MW=3000); polyalkyleneoxide-modified polydimethylsiloxane-dimethylsiloxane copolymer(MW=4000); (carboxylatepropyl)methylsiloxane-dimethylsiloxane copolymer(MW>1000); dimethylsiloxane-(60% PO-40% EO) block copolymer (MW=20,000);(hydroxyalkyl functional) methylsiloxane-dimethylsiloxane copolymer(MW=5000); aminopropylmethylsiloxane-dimethylsiloxane copolymerMW=4500); aminoethylaminopropylmethoxysiloxane-dimethylsiloxanecopolymer (MW>1000); glycidoxy propyl dimethoxy silyl end-blockeddimethyl siloxane polymer (MW=5000); methacryloxy propyl dimethyoxysilyl dimethyl siloxane polymer (MW=40,000); vinyl dimethoxy silylend-blocked dimethyl siloxane polymer (MW=6500); aminoethylaminopropyldimethoxy silyl end-blocked dimethyl siloxane polymer (MW=3800);amine-alkyl modified methylalkylaryl silicone polymer (MW=7800); epoxyfunctional dimethylpolysiloxane copolymer (MW=8300);dimethylpolysiloxane (MW=26,439);dodecylmethylsiloxane-hydroxypolyalkyleneoxypropyl methylsiloxanecopolymer (MW=1900);(dodecylmethylsiloxane)-(2-phenylpropylmethylsiloxane) copolymer(MW>1000) and polyalkylene oxide-modifiedpolydimethylsiloxane-dimethylsiloxane copolymer (MW=600).

[0022] The binder employed in the present invention includesconventional binders such as acrylamides, starch, urea resins, phenolresins, sodium silicates, epoxy resins, styrene-butadiene rubber,acrylic, neoprene, acrylonitrile and other nature or synthetic lattices.A highly preferred binder employed in the present invention is amodified formaldehyde type binder disclosed in U.S. application Ser. No.09/759,043, the entire content of which was previously incorporatedherein by reference. Specifically, the preferred binder is aformaldehyde binder containing about 0.1 to about 20 weight % of acrosslinked styrene/acrylic or methacrylic, (designated herein as(meth)acrylic), copolymer as a binder modifier. More preferably, theformaldehyde binder resin employed in the present invention containsfrom about 0.05 to about 15 weight % of a 0.05 to about 10 weight %crosslinked styrene/acrylic polymer modifier.

[0023] The formaldehyde type binder base is a thermosetting resin offormaldehyde in combination with urea, phenol, resorcinol, melamine ormixtures thereof. Of these, the formaldehyde/urea binder base ispreferred. The binder base contains a binder modifying amount of astyrene/acrylic resin containing a polyfunctional component whichcrosslinks with the copolymer resin during mat curing. The styrenecomponent in the resin can be unsubstituted or substituted on a ringcarbon atom with a lower alkyl, vinyl, allyl, chloro or phenyl group;however, from the standpoint of economics; notwithstanding the reducedflammability and high thermal stability of some of these substitutedtypes, unsubstituted styrene is most preferred.

[0024] The styrene/acrylic resin, which includes acrylic, methacrylicmoieties and mixtures thereof, contains a minor amount, e.g., betweenabout 0.05 to about 10 weight %, preferably between about 0.1 to about 5weight %, of a crosslinking agent, such as a polyfunctional amine,amide, or acrylonitrile. Alternatively, the polyfunctional crosslinkingagent may be any other polyfunctional crosslinking agent such as, forexample, a di- or tri-olefinically unsaturated hydrocarbon or otherconventional crosslinker that is reactive with the styrene/acryliccopolymer.

[0025] Of the above-mentioned polymer compositions, those providingself-crosslinkable characteristics are preferred. The (meth)acrylicpolymer is generally a mixture of (meth)acrylates and additionally maycontain (meth)acrylonitriles, (meth)acrylic acid and/or(meth)acrylamides as comonomers. One advantage of the preferred modifiedbinder is that it allows for curing at a lower temperature than wouldotherwise be required for a mat containing siloxane/formaldehyde typebinder alone. It is believed that this benefit is attributed to thecrosslinking of the modifier. Another advantage of the preferred binderis a degree of flexibility contributed by the styrene comonomer.

[0026] Reference is now made to the sole drawing accompanying thepresent application which is a top plan view illustrating the separationof a composite which comprises a glass fiber mat of the presentinvention having an asphalt coating which penetrates the mat. Theportions of the coated mat being separated are indicated by referencenumerals 12 and 14 with fibers 10 of different lengths bridging theseparated area and resisting disunion before total separation occurs.

[0027] For the manufacture of roofing shingles or BUR, a polysiloxanecontaining fiber glass mat with the above mentioned modifiedurea/formaldehyde binder is preferred. The dried, cured mat may becovered on one or both sides with a conventionally thick coating of astandard asphalt or asphalt compound to produce a composite roofingproduct which can be cut to any size or shape or used as undivided BURsheeting and packaged in pallets or rolls for shipment and subsequentinstallation. In the case of BUR roofing, however, coating or mopping ofthe mat with a hot surface coating of asphalt is generally delayed untila coarse sheeting is installed on the roof. The asphalt employed in thepresent invention for coating may additionally contain a conventionalantifungal, antibacterial, UV inhibitor and/or coloring agent.

[0028] The roofing product provided by the present invention is aproduct of conventional weight and somewhat increased flexibility whichmeets and exceeds the requirements of ASTM D-3462 testing. Thesignificantly improved tear strength of the present product results insavings in packaging and transportation of the product as well asdurability of the product when installed.

[0029] The following examples are provided to illustrate some of theadvantages that can be obtained from the present invention.

EXAMPLES 1-5 AND COMPARATIVE EXAMPLES 1-5

[0030] Testing Tear Strength of 3×2.5 inch samples of Shingles EmployingGlass Fiber Mats With Urea/Formaldehyde (UF) Modified Binder.

[0031] Tear test D-1922, as referenced in ASTM D-3462 (Jul. 10, 1997version), was used to determine the tear strength of various glass fibermats coated on both sides with a 25 mil coating of asphaltconventionally used in roofing materials. In summary, this test measuresthe force in grams required to tear apart the coated mat specimen usinga pendulum device. Acting by gravity, the pendulum swings through an arctearing the specimen from a precut slit. The test specimen is held atone end by the pendulum and on the opposite end by a stationary member.The loss in energy by the pendulum is indicated by a scale and pointer,which registers in the force required to tear apart the specimen.

[0032] To a wet web of 30-40 mm long glass fibers, derived from drainageof a white water slurry, was added at room temperature, a standardurea/formaldehyde binder containing 1% wt. styrene/butadiene polymermodifier to provide a fiber to polymer binder weight ratio of about75:25. The urea/formaldehyde binder was obtained from Dynea Co. and thestyrene/butadiene latex was from Dow Chemical Co. The basis weight ofthe fiber glass mat was controlled around 85 grams per square meter. Theweb containing fibers and polymer binders was then sprayed with anaqueous solution of poly(dimethylsiloxane), supplied by Chem-Trends asproduct RCTW B9296) to provide a polysiloxane concentration of 1% w/wwith respect to polymer binders. The resulting webs were then dried andcured at about 300° C. for a period of 10 seconds to produce cured,nonwoven mats, after which the mats were coated on both sides at 215° C.with filled asphalt (comprising 32% w/w asphalt and 68% w/w limestonefiller) using a two-roller coater.

[0033] In comparative examples 1-5, the same specimens were prepared asthe samples in examples 1-5, except they were not sprayed with thepolysiloxane solution.

[0034] The results of these tests are as reported in following Table 1.TABLE 1 Statistical significance Fibers Tear strength Standard comparedto the (wt. % and Polysiloxane gram force deviation comparative length)wt. % (gf) *(N = 9) examples Example No. 1 100% 30 mm 1 1573 173 Yes-at99% fiber confidence level 2 100% 40 mm 1 1498 259 Yes-at 99% fiberconfidence level 3  70% 30 mm 1 1313 155 Yes-at 99% fiber + 30%confidence level 40 mm fiber 4  50% 30 mm 1 1608 129 Yes-at 99% fiber +50% 40 mm confidence level fiber 5  30% 30 mm 1 2079 438 Yes-at 99%fiber + 70% confidence level 40 mm fiber Comparative Example No. 1 100%30 mm 0  992 134 fiber 2 100% 40 mm 0 1047 259 fiber 3  70% 30 mm 0  964 74 fiber + 30% 40 mm fiber 4  50% 30 mm 0  991  97 fiber + 50% 40 mmfiber 5  30% 30 mm 0 1105 245 fiber + 70% 40 mm fiber

[0035] The results in Table 1 establish that the presence of apolysiloxane in the glass mat having fibers of different lengthssubstantially improves the tear strength of shingles, especially thepolysiloxane containing mat having a higher percentage of longer fibers.The optimum percentage of longer fibers in the mat is around 40-80% inthe fiber mixture for the best tear strength of the shingle.

EXAMPLE 6 AND COMPARATIVE EXAMPLES 6-7

[0036] In example 6, the sample was prepared as the ones in examples 1-5with the basis weight of the fiber glass mat controlled around 85 gramsper square meter.

[0037] In comparative examples 6-7, the samples were prepared as theones in comparative examples 1-5 with the basis weight of the fiberglass mat controlled at 85 and 92 grams per square meter respectively.

[0038] The results of these tests are as reported in following Table 2.TABLE 2 Statistical significance Tear compared to Fibers Basic weightstrength Standard the (wt. % and of fiber glass Polysiloxane gram forcedeviation comparative length) mat (gsm) wt. % (gf) (N = 9) examplesExamples No. 6  30% 30 mm 85 1 1594 126 Yes-at 99% fiber + 70%confidence 40 mm level fiber Comparative examples 6  30% 30 mm 85 0 1256 91 fiber + 70% 40 mm fiber 7 100% 30 mm 92 0 1290 184 fiber

[0039] The results in Table 2 establish that the presence of apolysiloxane in the glass mat having fibers of different lengths notonly substantially improves the tear strength of shingle with the samebasis weight mat but also gives a higher shingle tear strength than witha higher basis weight mat.

[0040] While the present invention has been particularly shown anddescribed with respect to preferred embodiments thereof, it will beunderstood by those skilled in the art that the foregoing and otherchanges in forms and details may be made without departing from thespirit and scope of the present invention. It is therefore intended thatthe present invention not be limited to the exact forms and detailsdescribed and illustrated, but fall within the spirit and scope of theappended claims.

Having thus described our invention in detail, what we claim as new anddesire to secure by the Letters Patent is:
 1. A cured, non-woven matcomprising a mixture of fibers having different fiber lengths, saidfibers containing a polysiloxane compound, and fixedly distributed in abinder.
 2. The cured, non-woven mat of claim 1 wherein from about 0 toabout 100 weight % of said fibers have a fiber length of from about 0.5to about 60 mm, and from about 0 to about 100 weight % of said fibershave a fiber length of from about 10 to about 150 mm.
 3. The cured,non-woven mat of claim 2 wherein from about 20 to about 80 weight % ofsaid fibers have a fiber length of from about 10 to about 45 mm, andfrom about 20 to about 80 weight % of said fibers have a fiber length offrom about 30 to about 80 mm.
 4. The cured, non-woven mat of claim 1wherein said fibers comprise fibers of glass, wood, polyethylene,polypropylene, polyester, Nylon®, Orlon® or mixtures thereof.
 5. Thecured, non-woven mat of claim 4 wherein said fibers are glass fibershaving an average diameter of from about 1 to about 100 μm.
 6. Thecured, non-woven mat of claim 1 wherein said fibers are present in anamount of from about 50 to about 95 weight %, said polysiloxane ispresent in an amount of from about 0.001 to about 20 weight % and saidbinder is present in an amount of from about 5 to about 50 weight %. 7.The cured, non-woven mat of claim 6 wherein said fibers are present inan amount of from about 65 to about 90 weight %, said polysiloxane ispresent in an amount of from about 0.01 to about 10 weight % and saidbinder is present in an amount of from about 10 to about 35 weight %. 8.The cured, non-woven mat of claim 1 wherein said binder is formaldehydetype binder containing between about 0.1 and about 20 weight % of acrosslinked styrene/(meth)acrylic polymer binder modifier.
 9. The cured,non-woven mat of claim 8 wherein said formaldehyde type binder comprisesformaldehyde and a compound selected from the group consisting of urea,phenol, resorcinol, melamine and mixtures thereof.
 10. The cured,non-woven mat of claim 9 wherein said compound is urea.
 11. The cured,non-woven mat of claim 8 where the styrene/(meth)acrylic polymer iscrosslinked with a polyfunctional nitrogen-containing crosslinkingagent.
 12. The cured, non-woven mat of claim 1 wherein said polysiloxaneis a polyalkylsiloxane.
 13. The cured, non-woven mat of claim 12 whereinsaid polyalkylsiloxane is polydimethylsiloxane.
 14. The cured, non-wovenmat of claim 1 wherein said mat is a roofing material and is coated onat least one surface with asphalt.
 15. The cured, non-woven mat of claim1 wherein said mat is a glass mat employed in a roofing shingle.
 16. Anasphalt coated roofing material comprising a cured non-woven mat thatcomprises a mixture of fibers having different fiber lengths, saidfibers containing a polysiloxane compound, and fixedly distributed in abinder.
 17. The asphalt coated roofing material of claim 16 wherein fromabout 0 to about 100 weight % of said fibers have a fiber length of fromabout 0.5 to about 60 mm, and from about 0 to about 100 weight % of saidfibers have a fiber length of from about 10 to about 150 mm.
 18. Theasphalt coated roofing material of claim 16 wherein said fibers comprisefibers of glass, wood, polyethylene, polypropylene, polyester, Nylon®,Orlon® or mixtures thereof.
 19. The asphalt coated roofing material ofclaim 18 wherein said fibers are glass fibers having an average diameterof from about 1 to about 100 μm.
 20. The asphalt coated roofing materialof claim 16 wherein said fibers are present in an amount of from about50 to about 95 weight %, said polysiloxane is present in an amount offrom about 0.001 to about 20 weight % and said binder is present in anamount of from about 5 to about 50 weight %.
 21. The asphalt coatedroofing material of claim 16 wherein said binder is formaldehyde typebinder containing between about 0.1 and about 20 weight % of acrosslinked styrene/(meth)acrylic polymer binder modifier.
 22. Theasphalt coated roofing material of claim 21 wherein said formaldehydetype binder comprises formaldehyde and a compound selected from thegroup consisting of urea, phenol, resorcinol, melamine and mixturesthereof.
 23. The asphalt coated roofing material of claim 22 whereinsaid compound is urea.
 24. The asphalt coated roofing material of claim21 where the styrene/(meth)acrylic polymer is crosslinked with apolyfunctional nitrogen-containing crosslinking agent.
 25. The asphaltcoated roofing material of claim 16 wherein said polysiloxane is apolyalkylsiloxane.
 26. The asphalt coated roofing material of claim 25wherein said polyalkylsiloxane is polydimethylsiloxane.
 27. The asphaltcoating roofing material of claim 16 wherein said fibers are glassfibers.
 28. The asphalt coated roofing material of claim 16 wherein saidmaterial is a shingle.
 29. The asphalt coated roofing material of claim16 wherein said material is a sheet or roll.